Photomechanical printing.



UNITED STATES PA ENT OFFICE.

JOHN W. IPPERS, or NEWYORK, N. -Y., ASSIGNOR o ALBERT HENRY WALKER, or NEW YORK, N-. Y.

PHOTONIEQHANICAL PlRlNTlNC-a.

' Specification of Letters Patent.

' Patented Feb. 1 2, 19o'2'.

' Application filed November 2Q, 1906: Serial No. 345,012.

with non-intersecting parallel ridges on the peripheries of metal rollers, the function of the depressed printing-surfaces being tocarry color for deposit on continuous strips of cloth or paper and the function of the parallel ridges being to prevent the duotor, which removes the color from the nonprinting surfaces of the roller, from descending to the bottoms of the depressed printingsurfaces and removing a considerable part of the color therefrom. l

The relations of my invention to the prior art of photomechanical roller-printing can be learned by comparing this specification with Letters Patent of the United States No. 812,495, granted on my invention February 13, 1906, and Letters Patent of the United States No. 788,377, anted on the invention of Henry L. Reckar April 25, 1905. A copper roller having a depressed printin surface in the form of a star is indicated by Figure 3 of the drawings of my Patent No.,812,495 but that printing-surface is so small in area that it does not require any parallel ridges or other projections rising upward from its bottom to prevent the ductor from descending into that depression and removing any considerable amount of color therefrom. The specificaa tion of that patent does not, therefore, attend to that subject; but the Reckard patent, No. 788,377, does attend to that subject by means of a particular method fully set forth in the specification of that patent and constituting an essential part of each of the first six claims thereof. Fig. 9 of that Reckard patent may be taken to represent the periphery of a metal roller provided'with a depressed printin -surface having the shape of a reversed letter R and having diagonal parallel ridges rising upward from the bottom of that depressed printing area and intersecting with the black non-printing area of the periphery of that roller. Close inspection of Fig. 9 of that Reckard patent will show that the black diagonal lines on the reversed letter R intersect at their ends with theplain black areas of the figure, and careful study of the specification of the 'Reckard patent will show that such intersections must always result from the Reckard methodof making those black diagonal lines and that the parallel diagonal ridges of metal which ultimately resuit in the depressed printing-surfaces of a metal roller made by the Reckard process must intersect with the non-printing surfaces of that roller.

The Reckard method of. making parallel ridges in the bottoms of depressed printing surfaces of metal rollers, while availableand useful for that purpose, is not perfect, because perfection requires that the parallel ridges in the bottoms of'depressed printing-' surfaces of metal rollers shall stop slightly short of intersecting at their ends with the non-printing surfaces of such rollers, as the diagonal parallel lines of Fig. 10 of the drawings which accompany this specification are shown as stopping short of intersecting with the black Background of that figure.

The desirability of leaving a narrow and uniformly-depressed border at the edge of a depressed printing-surface of a metal printing-roller arises from the desirability of a plying color with smooth continuity at th edge of every such deposit and from the fact that where the parallelridges quite reach and intersect with the non-printing surfaces of an intaglio metal printing-roller the resulting edges of the deposit of color are not quite sharply and evenly defined. -Where the metal parallel ridges are located on the depressed printing-surfaces of ametal roller, as the black parallel lines of Fig. 10 of my present drawings are shown to be located upon the white parallelogram of that figure the color which is left upon the periphery of the roller after the ductor has done its work thereon is de osited in the grooves which are represente by the white lines of that figure. When that color is transferred from'such a metal roller to a strip of cloth, that ap lication is in the form of corresponding ines; but capillary attraction immediately operates to blend together all the color deposited on the cloth from the diagonal grooves, so as to result in a continuous application of color to the cloth over that part of its surface which was opposite to the depressed surface roller in the printing-machine. Capillary attraction will also causethe color to spread slightly outward from the lines which receive deposits of color from the outer continuous grooves of the depressed printing-surface but inasmuch as those outer grooves are uniform the outward spreading of the color will also be uniform, whereas if the parallel copper ridges extended quite to the non-printing surfacesof the roller, hile capillary attracuon w ould operate to cover the cloth opposite to the de-' pressed printing-surface of the roller, the

outer edges of that deposit would appear to be slightly rough and irregular instead of be ing even and continuous, as they will be if a continuous depression is made all around the edges-of the depressed printing-surface. 'lhe reason why extensions of the parallel copper ridges quite to the non-printing surfacesof the-roller would cause the outer edgesof the deposit of color on the cloth to be slightly rough and irregular resides in the fact that the separate capillary deposits of color within the cloth between the unconnected ends of the parallel grooves would not be quite equal in. copiousness to the separate direct deposits of color upon the cloth from the ends of the parallel grooves themselves.

The nature of my present invention consists in what I believe to-be the first photomechanical method of so making parallel ridges in the bottoms of depressed printingsurfaces of metal rollers that the ends of those ridges will not intersect with the nonpri'nting surfaces of the rollers; and I will now proceedto describe that method in detail with the-assistance of the accompanying ten figures of drawings. p

Fig. 1 represents a translucent glass sheet having thereon a design consisting ofa flat area of opaque surface in the form of a rectangle. Fig. 2 is a view of a lithographic stone which has photographically received an acid-resisting film upon the surface, which is represented in the figure by a hollow black rectangle and the naked surface of'whieh stone has been thereupon etched down to a lower level to constitute the depressed sur-' face, which is indicated by numeral 2. Fig. 3 is a central vertical cross-section of the stone of Fig'. 2. Fig- 4 is a view ofa translucent glass sheet which has been provided with parallel black lines separated by parallel transparent lines of the same width upon one of its sides. The black lines upon the sheet of Fig. 4 are permanent and may be produced in. an of the ways in which ermanent black ines are made across g ass plates to beused as'screens of light in the art of photomechanical printing. Fig. 5 is a view of another lithographic stone, which has. been provided photographically through the translucentscreen of Fig. 4, with narrow parallel printing-surfaces represented by the black parallel diagonal lines of that figure and separated by narrow non-printing surof Fig. 5. vFig. 7 is a vertical cross-section ofthe stone of Figs. 2 and 3,with' the sheet of transfer-paper 6 pressed down, upon the upper surface of the stone, including its black faces represented-by the white diagonal lines border and its depressed area 2 within that border. Fig. 8 is a view of the stone of Figs; 2, 3, and 7 after the sheet of transfer-paper 6 has been removed therefrom. .Fig. 9 is a vertical cross-section of the stone of Fig. 8

with a sheet of. elastic white cardboard 10' pressed down thereon so as to receive an impression of ink therefrom. Fig. 10 is a view of thatsheet of finewhite cardboard after it has received that impression of ink and has and by adding thereto three drams of bichro mate of ammonia -dissolved in four and onehalf ounces of water and by addin fifteen drops of liquid ammonia to the who 0, and I kee and use this sensitizing solution in a dart room. I then warm theplain lithographic stoneby pouring hot water over it, and then I flow'the sensitizing solution over it and dry thereon the film thus deposited. Thereupon I clamp the translucent glass plate of Fig. 1 down upon the sensitized stc ne and in close contact therewith. Then I expose the sensitized stone to light through the translucent glass plate, about one minute if the light be direct sunlight or about eight minutes if it be clear north daylight. I next remove the translucent glass late from the plain lithograhpic stone in a ark room and at once roll transfer-ink evenly-over the entire sensitizedsurface of the stcne. I'th'en flow cold water over that inked surface and wash away with a cotton ball all the ink which was deposited on that area of the stone which wasunder the opaque area of the glass plate during the ex osure; but that washing does not disturb t e ink 0 these areas;- of the stone which were, un er the translucent borderof the glass plate at that time. Thereupcn I dust powdered rosin over the stone, and it is taken by the inked areas of the stone, but not by the area from which the ink was washed away and which is I next'apply to the stone.

warm water dissolved together and filtered.

I leave that strong nitric-acid solution on the stone two or three minutes, more orless, until it has reduced the level of the naked area-of the stone one-thirty-s'econd of'an inch, more or less, below the enameled areas of the stone.

'Thereupon I wash away the surplus solution with water and then dry the stone till no Water remains thereon. I next apply to the stone a solution of one ounce of acetic acidin ten ounces of water,"the function of which application is tomake the naked area of the. stone receptive of greasy ink instead of being' repellent thereof, as it. would be otherwise as the result of the application of the strong ii-- trio-acid solution thereto.

The ruled glass screen of Fig, '4 having been made or purchased, as the case may be,

is a'perrnanent utensil which is usable in any 7 number of instances of the performance of about one-eightieth of an inch wide, though I graphic face crossed by parallel ink-receiving mg aproper sheet down upon the stone of F 5 after that my process,

, SilZIZBd', 1 4

' The sheet of transfer-paper of Fig. 6 is not The parallel opaque and transparent lines on thatscreen should each be they are shown wider than that in Fig. 4.

The lithographic stone of Fig. 5 has a planonon-ink-receiving lines,{"which ink receivin lines are indicated by the black lines" and w ich non-ink-recoiving lines are indicated by-the white lines of Fig. 5. Those receivingand non-ink-receiving lines are producedin any proper photolithographic manher and by the action of light p'assin through the ruled screen of Fig. 4 when t at ruled screen is clamped down upon the stone of Fig. 5 afterth'at stone has been properly sen .a' permanent utensil, and such a sheet requires to be made for each instance of the performance of my process by simply pressof white transfer-paper stone has been properly'rolle with transferink, so that-the sheet'of transfer-paper may be provided with heavily and uniformly inked lines corresponding m width with the inked'lines' on the stone 'of Fig; 5. The

transfer-paper of Fig. 6 being thus freshly inked is pressed immediately down upon the lithographic stone of Figs. 2 and 3, as shown in Fig. 7. Those portions of the inked lines of the transfer-paper 6 which arethus pressed down. upon the enameled. black border of of equalparts 0 .pentine,

--mov .phalt. At this stage of the process the inked the stone of Figs. 2 and 3 simply print black parallel lines acrosstha't black border, but do not in so doing efliect any appreciable result. Thoseportions of the inked lines of the transfer-paper 6 which are'pressed down upon the naked, depressed area 2 of the stone of Figs. 2 and S'deposit parallel lines of black ink across that area, as shown in Fig. 8, and the black lines thus deposited may or may not intersect with the inner edges ofthe black enameled border of the stone, becausethe transfer-paper is flexible and may or may not press quite into the corners 7 of the depressed surface 2. I next apply a weak nitric-acid solution to the enameled and inked stone of Fig. 8, which solution consists of five ounces of nitric acid of thirtyfive per cent. strength, with two pounds of gum-arabic and three pints of water'dissolved'and filtered. .I then apply .tothe stone a solution oftwo ounces of gum: arable and S1X ounces of water in a .thin and even film and allow it to dry on the stone;

but thisapplication is so thin'that it does not adhere to the enameled areas of the stone nor to its inked diagonal lines, but only tothe narrow naked spaces between those f lines. 'I-then ap ly to the stone a-mixture asphalt-varnish and turwhich mixture removes all the ink which was deposited on the stone; by the transfer-sheet 6, but does not disturb the enameled border'of the stone nor the gum which. adheres to thc'uninked spaces be-- tween the inked. lines on the depressed area 2 ofthe stone. I then apply water with a spo" e to that depressed area,- and thus-rethat gum,.but do not disturb the asdiagonal. lines are covered with asphalt,

left naked. Thereupon water is applied'to while thenarrow'spac'es between them are the stone, which is absorbed by its naked areas, but'is repelled by its enameled areas and by those which are covered with asphalt.

Transfer-inkis then applied to the stone and is received by the enameled border and by the areas which are covered with asphalt, but is not received by the narrow naked spaces between those areas. I then dust powdered rosin over the stone, which is taken by the inked diagonal lines, but not by the spaces between those lines. I then change .that'rosined inkinto enamel by the application of heat, and then I etch the spaces between the enameled lines with my stron nitric-acid solution a few seconds. I In this condition of the stone the enameled diagonal lines are raised somewhat. above the naked spaces between them, and those spaces are repellent of ink, becausethey were last etched with nitric acid. I'then roll the entire stone with lithographic ink, which ink is received by'the enameledhorder of the stone and by the enameled diagonal lines across the depressed surface 2 of the stone. I then press a sheet of white elastic cardboard down upon the stone, as shown in Fig. 9.v That cardboard being comparatively stiff 5 does not bend sharply enough to reach into diately adjacent to those corners. For this reason the cardboard .when removed from the stone will have received a continuous printin of ink from the black enameled border of the stone and. will have received printings of ink from the black enameled lines on the floor of the-depressed area 2 of the stone; but threads of those black lines of ink-printing stop short of intersection with the printed border of the cardboard to about the extent which they are shown as doing in Fig. 10.

The printed. cardboard sheet of Fig. is the net product of all the transactions thus far described in this specification. That figure is presented as representative of any simpie or complex design, which when multi-' plied or not multiplied may constitute a pattern'exactly large enough to cover the periphc'ry of a metal printing-roller. For example, such a design may cover a paralleloam six inches by five and a quarter inches 111 dimensions, and the surface of that parallelogram may be composed of any number of regular or Irr lar white areas provided with parallel black lines and surrounded b fiat black spaces with which .-those'blac lines stop short of intersecting.

Having produced by the program above set forth a sheet of cardboard having dimensions six inches by five and a quarter inches and having a more or'less complicated and multi-farious design representedthreon by white areas occupied by non-intersectin black lines, like the white area of Fig. 10,

can produce seventeen duplicates of that sheet by printin white cardboard rom the same lithographic stone as that from which the first one was printed. I can then fasten the eighteen duplicate sheets thus produced upon a fiat wooden board 7 or zinc sheet without any spaces between them, so that they will exactl cover a parallelogram having a surface of t irty-six inches b fifteen and threequarter inches, and which surface may be identical in dimensions with the periphery of a metal roller thirty-six inches long and about five and one-quarter inches in diam- -eter.

The shape taken by the cardboard 'duction of one sheet of cardboard, sue

on seventeen sheets of The eighteen sheets of cardboard being thus combined together upon a flat board may be made to compose a harmonious pattern combined of eighteen repetitions of one original design, and every space occupied by non-intersecting diagonal lines, which appears upon the wholepattern, may ultimately result; in a continuous deposit of color made on astrip of cloth from 1a metal roller and the entire attern may be printed on that strip, once or each revolution of theroller in a printing-machine.

My present invention stops with the roas that typically represented'by Fig. 10, for the above-suggested multiplication of that design does not involve invention and because the proper process for proceeding forward from the design thus multiplied to printing the complete pattern upon a" continuous strip of 0 0th is described in my Letters Pat ent No. 812,495, of February 13, 1906. In that patent, Fig. 1 may be taken as representative of a translucent hotographic nega- 'tive having dimensions t 'rty-six inches by fifteen and threeuarter inches and made in a lar e photograp '0 camera from the combiner? cardboard pattern which is above set forth. Such a photogra hic negative being made with man u ormly translucent areas and many un formly-opaque areas, that negative may be used to photographically print upon a flat gelatin plate of corresponding dimensions, and that fiat gelatin plate may be then developed and drled and supplied With transfer-ink and used to transfer that ink to the periphery of a metal roller, and that metal roller, being etched and otherwise treated, as set forth in that patent, may be used in a printing-machine to ap ly color to' a continuous strip of cloth. In that use the parallel ridges in the bottoms of the depressed printing-surfacesof the roller operate to prevent the ductor from scraping the color out of those depressions, and the nonintersection of the ends of the ridges With the non-printing surfaces of the roller results in a highly desirable sharpness of edge in the printing done on the cloth from those depressed printing-surfaces, while capillary attraction results in blending into a continuous deposit all the color which reaches the clot from the grooves between the ridges.

A lithographic stone is said in the foregoing description to be the material of the block of Figs; 2', 3, 7, 8, and 9; but a metal plate may be enlrployed instead of a lithographic stone to pc orm the function of that block in Sllb'.

stantially the sameway in which that function is performed by'a lithographic stone, having a depressed-surface like that indicated by the numeral 2, and the method of sensitizing the surface of a metal plate to fit it for exposure through a sheet which is partly't'ransparent and partly opaque and the method of developing that exposed surface and the method of etching down some portion or portions of that developed surface into de ression and the method of preparing the sur aces of an etched metal plate to properly print from its different levels upon cardboard will differ in particulars, which will be apparent to photomechanical engravers, from those corresponding methods which have herein been described as applicable to a lithographic stone for those purposes. So, also, a lithographic stone or metal plate may mechanically receive an acid-resisting film or deposit on some portion or portions of its surface instead of receiving such a film or deposit photographically, and thereupon the other portion or portions of its surface may be etched down to a lower level for the purposes described in this specification. Moreover, a lithogra hic stone or metal plate having been rovide with a depressed surface like'that indicated by the numeral 2 may have that depressed surface provided with parallel printing-lines by some other process than that described in this specification for that purpose. My invention is not limited to the particular methods or to the particular materials which it describes; but it is limited to the processes which are defined in the following claims' I claim as my invention- 1. Making a photographically sensitive surface on a lithographic stone or metal plate: exposing that sensitive surface to light through a sheet whichis partly transparent and partly opaque: developing that exposed surface into a condition in which whatever area of the stone or plate was under a transparent area of the sheet during the exposure,

will resist etching liquid, while whatever area of the stone or plate was then under an opaque area of the sheet, will not resist etching liquid: etching down into a depressed area, whatever areaof the stone or plate is thus made subject to etching: putting the stone or plate into a condition in which it will receive ink over any undepressed area, and will receive ink on parallel lines on the floor of any depressed area thereof, but will not receive ink on the parallel spaces between those parallel lines: applying ink to those surfaces and lines of the stone or plate which will receive ink: printing a continuous area from any undepressed surface of the stone or plate upon a sheet of cardboard, while print ing parallel lines upon the same sheet from Whatever area of the stone or plate is depressed, but which parallel lines stop short of intersecting with any continuous printed area on the cardboard. D

2. Preparing a surface on a lithographic stone or metal plate, so that some of its areas will resist etching liquid, while other of its areas will not resist etching liquidz' etching down into a de ressed area, whatever area of the stone or plate is thus made subject to etching: putting the stone or plate into a condition in which it will receive ink over any unde ressed area, and will receive ink on parallel ines on the floor of any depressed area thereof, but will not receive ink on the parallel spaces between those parallel lines: a plying ink to those surfaces and lines of the stone or plate which will receive ink: printing a continuous area from any undepressed surface of the stone or plate upon a sheet of cardboard, while printing parallel lines upon the same sheet from whatever area of the stone or plate is depressed, but which parallel lines stop short of intersecting with any continuous printed area on the cardboard.

Executed November 24, 1906.

JOHN W. IPPERS. Witnesses:

ALBERT H. WALKER, NARCISO C. DONATO. 

